Conventionally, on a production line for products such as foods, a defect inspection is performed by using an X-ray inspection apparatus in order to prevent the shipment of defective products, if any, that are contaminated with foreign matter or cracked. Such an X-ray inspection apparatus irradiates target objects being continuously conveyed by a transport conveyor with X-rays. The transmittance state of those X-rays is detected by an X-ray receiving unit, and a determination is made as to whether each target object is contaminated with foreign matter, whether it has cracks, whether there is a shortage in the number of items it contains, and the like.
For example, Japanese Laid-Open Patent Application Publication No. 10-339707 discloses an X-ray diffraction apparatus (X-ray inspection apparatus), in which, for the intensity curve and the intensity level with respect to the angle of the background data, the apparatus determines an intensity curve based on the measurement data of a standard sample, adjusts the level of the intensity curve based on the intensity level, and thereby can obtain adequate background data independent of the object being measured.